This chapter is a review of magnetic materials and how they behave. It begins by discussing the significance of ferromagnetism and comparing the Curie temperature of several ferromagnetic elements. It then discusses the concept of magnetic domains and illustrates how flux paths, and magnetostatic energy, vary based on the size of the domain. It also discusses the process of magnetization and compares and contrasts hard and soft magnetic materials.

This chapter discusses the advantages of using powder metallurgy to produce magnetic materials, particularly its ability to control chemistry and near-net shape. It also explains how process parameters and powder characteristics influence the physical and magnetic properties of common stainless steels.

This article discusses the compositions, structures, and properties of the most common grades of soft magnetic metals and permanent magnet alloys. It explains how alloying additions and impurities affect the magnetic properties of these materials, which include commercially pure and phosphorus irons, low-carbon and silicon steels, ferritic stainless steels, and nickel-iron and iron-cobalt alloys.

The physical properties of a material are those properties that can be measured or characterized without the application of force and without changing material identity. This chapter discusses in detail the common physical properties of metals, namely density, electrical properties, thermal properties, magnetic properties, and optical properties. Some physical properties for a number of metals are given in a table.

This chapter provides a view of magnetism in materials used at low temperatures. The discussion covers the concepts, definitions, and systems of units that are unique to the study of magnetic properties. The chapter provides a description of some of the techniques and devices used for determining magnetic properties.

Nonferrous metals are of commercial interest both as engineering materials and as alloying agents. This chapter addresses both roles, discussing the properties, processing characteristics, and applications of several categories of nonferrous metals, including light metals, corrosion-resistance alloys, superalloys, refractory metals, low-melting-point metals, reactive metals, precious metals, rare earth metals, and metalloids or semimetals. It also provides a brief summary on special-purpose materials, including uranium, vanadium, magnetic alloys, and thermocouple materials.

This chapter addresses some of the challenges involved in materials selection, providing context for much of the information presented in the book. It describes a typical four-step design scenario, noting material-related considerations and information needs. It explains how design decisions are complicated by the interconnected nature of material properties, design geometry, and manufacturing requirements and effects. The chapter also assesses the design impact of several materials and discusses codes, standards, and specifications.

This chapter explains how powder metallurgy technologies are being leveraged for the production of automotive components, electric motors, rare-earth permanent magnets, and the infrastructure for high-speed rail transport.

This chapter describes the physical properties of steels used for castings. The properties covered include density, modulus of elasticity, Poisson's ratio, shear modulus, thermal expansion, thermal conductivity, specific heat, thermal diffusivity, electrical resistivity, and magnetic properties.

This article discusses the general purpose of alloying and identifies some of the material properties and behaviors that can be improved by adding various elements to the base metal. It explains how alloying can make metals stronger and more resistant to corrosion and wear as well as easier to cast, weld, form, and machine. It also discusses some of the alloying techniques that have been developed to address problems stemming from dissimilarities between the base metal and alloying or inoculate material.

Liquid penetrant, magnetic particle, and eddy current inspection are used to detect surface flaws. This chapter is a detailed account of the physical principles, process description, equipment requirements, selection criteria, advantages, limitations, and applications of these surface flaw detection techniques.

This chapter discusses the design and operating principles of various types of electromagnetic coils. It explains how induction coils are classified based on the direction of the eddy currents they induce in the workpiece and the corresponding orientation, whether longitudinal or transverse, of the associated magnetic flux. It then discusses the factors that influence coil design and selection, including coupling efficiency, frequency, the number and spacing of turns, and the use of flux intensifiers. It also includes images and illustrations of various types of coils and coil geometries for basic as well as special purpose applications.

This appendix provides practical information on induction coils and how they are made. It discusses soldering methods, preferred materials, design challenges, and best practices and procedures. It also discusses the design, construction, and application of magnetic flux concentrators and the growing use of computer simulation.

Nickel and nickel alloys have an excellent combination of corrosion, oxidation, and heat resistance, combined with good mechanical properties. Nickel alloys can be divided into alloys that combine corrosion and heat resistance, superalloys for high-temperature applications, and special nickel alloys. Corrosion- and heat-resistant nickel alloys include commercially pure and low-alloy nickels, nickel-copper alloys, nickel-molybdenum and nickel-silicon alloys, nickel-chromium-iron alloys, nickel-chromium-molybdenum alloys, and nickel-chromium-iron-molybdenum-copper alloys. Special nickel alloys include electrical-resistance alloys, low-expansion alloys, magnetically soft alloys, and shape memory alloys. This chapter discusses the metallurgy, nominal composition, properties, applications, advantages, and disadvantages of these alloys. It also provides information on cobalt wear-resistant alloys and cobalt corrosion-resistant alloys.

This chapter focuses on the inspection of steel bars for the detection and evaluation of flaws. The principles involved also apply, for the most part, to the inspection of steel wire. The nondestructive inspection methods discussed include magnetic particle inspection, liquid penetrant inspection, ultrasonic inspection, and electromagnetic inspection. Eddy current and magnetic permeability are also covered.